This invention generally relates to a non-invasive diagnostic system for the monitoring of physiological parameters. More specifically the present invention relates to measuring and processing bio-impedance. Furthermore, the present invention relates to a method for disclosing a physiological indication using a bio-impedance measuring system.
There are numerous relevant technologies relates to impedance measuring physiological monitoring systems; and to methods of data analysis, particularly useful for extracting physiologically significant detail from impedance measurements. Consideration of such useful data analysis methods has heretofore not been appreciated; especially in that data analysis can be so useful for extracting physiologically significant detail from (prolonged) impedance measurements.
Certain aspects of the present invention may be found in the published and subsequently abandoned application PCT/US95/14549 xe2x80x9cUniversal Indicator for Physiological and Pathological Conditionsxe2x80x9d (by the inventors of the present invention); based on abandoned Israel application 111535. This application was abandoned because it did not contain sufficient disclosure for allowing the invention to be implemented, and because it became understood that significant additional research was necessary (by the inventors) in order to properly implement a valid embodiment. Nevertheless, the prior art references related therein-present partial teachings (of closely related problems) which are relevant to the present invention; and these references are:
Multinda J. H., Visser K. R. Estimation of blood pressure-related parameters by electrical impedance measurement. The Netherlands. J-Appl-Physiol. November 1992; 73(5):1946-57.
Ratzmann K. P. et al. Prevalence of peripheral and automic neuropathy in newly diagnosed type (non-insulin dependent) diabetes. J-Diabet-Compliacations. January-March 1991; 5(1):1-5.
Librenti M. C. et al Evaluation of an impedance measurement method for determining body composition in diabetes subjects and normal controls. Minerva-Endecrinol. January-March 1991; 16(1):27-30.
Wang L, Peterson R. P. Respratory effects on cardiac related impedance indices measured under voluntary cardio-respiratory synchronization. (VCRS) U.S. Med-Biol-Eng-Comput. September 1991; 29(5):505-10.
And Patents: Israel#71468 for A rheoplethsmographic device; and France#35484 for Apnea Monitoring method and apparatus.
Subsequent to the PCT application withdrawal, additional prior art citations have been found which further present relevant matter for understand the teachings of the present invention; and these citations (all being USA patents) are:
U.S. Pat. No. 3,835,840 Impedance plethysmography method and apparatus.
U.S. Pat. No. 3,949,736 Circuit for automatically deriving and measuring relative voltages associated with impedance components of a biological object.
U.S. Pat. No. 4,450,527 Noninvasive continuous cardiac output monitor.
U.S. Pat. No. 5,241,963 Method for detecting the onset and relative degree of atherosclerosis in humans.
U.S. Pat. No. 5,280,429 Method and apparatus for displaying multi-frequency bio-impedance.
U.S. Pat. No. 5,343,867 Method and apparatus for detecting the onset and relative degree of atherosclerosis in humans.
U.S. Pat. No. 5,421,344 Method and means of determining the health condition of a living creature.
U.S. Pat. No. 5,449,000 System for body impedance data acquisition utilizing segmental impedance and multiple frequency impedance.
U.S. Pat. No. 5,454,377 Method for measuring the myocardial electrical impedance spectrum.
U.S. Pat. No. 5,469,859 Non-invasive method and device for collecting measurements representing body activity and determining cardiorespiratory parameters of the human body based upon the measurements collected.
Accordingly, it would be considered a preferable result to allow prolonged impedance measurements outside of the clinical settings of the prior art, to provide a new avenue for collecting data on normal activity (human or otherwise), or to provide facile diagnostic monitoring options for patients presently restricted to remain in proximity to diagnostic professionals. Furthermore, it would be considered a preferable result to be able to disclose physiological events, especially those that may significantly effect other modalities of medical intervention.
The present invention relates to a non-invasive diagnostic physiological monitoring system for mammals, particulary humans, comprising:
(a.) at least two surface contact electrodes;
(b.) means for holding these electrodes in contact with an exterior surface of a mammal;
(c.) means for pairing these electrodes;
(d.) an electronic block coupled to at least one of the pairings wherein the block includes a transmitter for transmitting a predetermined electrical signal to a first pair of electrodes in the pairing, and a detector for detecting electrical impedance characteristics on the first pair of electrodes or on a second pair of electrodes in the pairing; and
(e.) a signal processor coupled to the detector wherein the electrical impedance characteristics are divided into at least two groups by frequency.
A significant aspect of the present invention relates to data analysis performed at the signal processor (or at the electronic block). This analysis is particularly useful for extracting physiologically significant detail (xe2x80x9ccharacteristicsxe2x80x9d) from the impedance measurements. Characteristics may include measures that aid in the discernment of physiological indications pertaining to the state of the blood, veins, arteries, heart, or lungs.
On the one hand, the present invention measures multiple characteristics (e.g. on humans) in less than about 10 seconds (using an un-optimized prototype of the present system). This speed of measurement makes the system of the present invention a preferred diagnostic tool for emergency medical services personnel, since it can reveal measures of critical life-threatening internal injuries.
On the other hand, the present invention (being facile, portable, and unobtrusive) can be used to accumulate a broad collection of characteristics over a prolonged continuous measurement period of days. This may provide a patient profile (e.g. for humans) that is not otherwise obtainable.
Another interesting application of the present application relates to use for mammals (e.g. non-humans), such as cows or horses. This is a valuable tool for veterinarians, animal breeders, meat-packers, and other animal byproduct workers. For example, the present invention may provide an economically significant indication of a cow""s suitability for Jewish ritual slaughter (wherein the internal organs must be intact) or of the cardiovascular capacity of a racehorse.
Normally use of the system of the present invention includes (methodologically) an initialization step of automatically normalizing the data values of the measured impedance according to five specific frequency separable data characteristics, the computing of a subsequent plurality of relative variations thereof, and the calculating of normalized diagnostic indices therefrom. The five specific data characteristics are the measured starting values for the constant composing impedance, the amplitude of the pulse wave, the frequency of the pulse wave, the amplitude of the breath wave, and the frequency of the breath wave.
The present invention also relates to a method for disclosing a physiological indication in a mammal, particularly a human. This method is especially useful for its convenience in disclosing of signal signature events in bio-impedance measurements. This disclosing is especially significant, for many discrete populations (or sub-populations) of subjects, in that the discernment of important physiological indications is provided thereby; or is otherwise probabilistically suggested.
Furthermore, it should be noted that the system of the present invention operates substantially according to the method of the present invention.